The present invention relates to a covering element, preferably for roofs, of the type commonly known as a shingle. In the publically accessible Norwegian application No. 75.2695, a particular type of covering element is described in which a plastic film covering an asphalt layer on the underside of the shingle is further coated with a release agent.
It is common practice that covering elements of the type described in Norwegian application No. 75.2695, as well as conventional shingle types in which the plastic film is not coated with a release agent, are shaped in such a manner that the shingle will to some degree simulate roofing slate or roofing tile when mounted on a roof. The conventional shingle can be of the general type described in U.S. Pat. No. 2,963,405 and a particularly preferred embodiment is a shingle provided with "tongues" such as illustrated in FIG. 6 of U.S. Pat. No. 2,863,405. However, since the known shingle types normally have a thickness in the range 3-4 mm, they will not provide the same relief effect which can be obtained by the normally thicker roofing tiles when laid on a roof.
The present invention provides a shingle type which has a thickness such that the laid shingle will better simulate a roofing tile and hence will give an enhancement relief effect.
In Danish Pat. No. 105,177, a bituminous roofing felt is claimed, the complete underside of which is covered with a layer of porous, particulated particles of fired clay. The purpose of the particulated material is to provide ventilation in order that trapped moisture, for instance from a concrete substrate, can be permitted to escape via the channels formed by the particulated material.